In a series circuit, the EN = IT × RN formula is used to determine the voltage drop across a component.

• A. current frequency
• B. power surge
• C. voltage drop
• D. wattage

Answer: (C)

Voltage drop is what you get when you apply Ohm’s law to a component. EN = IT × RN is just V = I × R written with different symbol names, so the voltage across that component equals the current through it times its resistance. In a series circuit the same current flows through every component, and summing these voltage drops gives the total source voltage. The other options aren’t describing a voltage drop: frequency is cycles per second, a power surge is a transient event, and wattage is a measure of power (P = V × I or I²R), not the voltage across a component.